RE: a great sandwich 40 years ago - still around?
FCF, I wonder if that's related to Elsie's in Harvard Square? When I was a starving BU student in the late 70s they opened a location in Kenmore. Their signature was, indeed, a Roast Beef on a puffy kaiser with red onion and Russian and I recall lemonade. The quality was pretty poor, usually tasted like day-old supermarket deli beef, but it was cheap and filling, and as you say, even then the combination was a bit exotic.
On the web it looks as though they still have their location on Mt. Auburn St. in Harvard Square. I ate there once over ten years ago and it lived up to memory, poorly. Still cheap for the neighborhood, but a bit skimpy and stale.
Anyone eat at Elsie's in Cambridge more recently or know anything of the history?